Figure 24.

(a) General structure of alternating Aib-ACPC hexamers and heptamers (Refs. [261,262,263,264,265]); (b) SEM images of foldectures created from Boc-(Aib-ACPC)₃-OBn added to P123 aqueous solutions at (top) 0.0 g L⁻¹, (middle) 0.015 g L⁻¹, and (bottom) 8 g L⁻¹, and plausible mechanism for the formation of parallelogram plate-shaped foldectures. The common prismatic nucleation network is composed of alternating antiparallel layers (in blue and red) that have the highly hydrophobic faces lying in the b-c plane, whereas the hydrophilic faces lie in the two other planes. In pure water, the growth occurs much faster along the a direction, in order to avoid the increase in exposed hydrophobic surface (rod-shaped morphology) while in the presence of P123 the growth along axis a is suppressed and the elongation occurs in the other two directions (parallelogram plate-shaped foldectures) (adapted with permission from Ref. [261]); (c) SEM images of foldectures self-assembled from Boc-(Aib-ACPC)₃-Aib-OBn in distilled water (F₀, also with representations) and in 8 g L⁻¹ (F₁), 24 g L⁻¹ (F₂), 40 g L⁻¹ (F₃), and 48 g L⁻¹ (F₄) aqueous solutions of P123 (insets: TEM images with scale bars = 1 µm) (adapted with permission from Ref. [262]); (d) General structure of alternating Aib-ACPC pentamers with different caps (Ref. [265]); (e) Structure of cyclopropanoyl-(ACPC-Aib)₃-OBn hexamer (Ref. [265]); (f) SEM images of foldectures obtained from pentamers R₁-(Aib-ACPC)₂-Aib-OBn in 8 g L⁻¹ aqueous solutions of P123 (R₁ = Boc (left); cyclopropanoyl (middle); isopropanoyl (right)) (adapted with permission from Ref. [265]).